A light emitting device, for example, a light emitting diode (LED), is a type of a semiconductor device which converts electrical energy into light. The light emitting diode replaces an existing phosphor lamp, incandescent lamp, or the like and is considered as a next-generation light source.
Since the light emitting diode generates light by using a semiconductor device, the light emitting diode consumes very low power, as compared to an incandescent lamp which generates light by heating tungsten or a phosphor lamp which generates light by colliding ultraviolet rays generated through high pressure discharge with a phosphor.
Also, since the light emitting diode generates light by using a potential gap of the semiconductor element, the light emitting diode has a long lifespan, a fast response time, and environment-friendly characteristics, as compared to the existing light source.
Accordingly, much research has been conducted to replace the existing light source with a light emitting diode. The light emitting diode is increasingly used as a light source of a lighting apparatus such as various lamps used indoor and outdoor, a display device, an electronic board, a streetlamp, and the like.